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How to test a 1994 LS400 EGR Valve


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I'm looking for Test procedure for an EGR valve off my 1994 LS400. This is not the vacuum type but has the electronic stepper motor. Lexus Part No 25620-50020. This EGR has the same connector as the IAC. I have the test procedure for the IAC to move the valve open and closed (Applying VDC to pins 1-4 in sequence to close and 4-1 to open) and the EGR appears to have the same design (But bigger coil) and connector so I tried the IAC procedure on the EGR, no valve movement. I have 2 of these EGRs and the IAC procedure doesn't work with either. 2 bad EGRs, maybe but I doubt it. So I'm thinking that the test procedure is slightly different for the EGR. If anyone knows where to get a copy of the the EGR test procedure to test the operation of the valve I would love to get a copy. Any other feedback is welcome. Thanks.

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And if you get the information please post it here for everyone else. If you don't have a manual your choices are, go to the dealer and ask to look at one, or go to the Toyota TIS site and down load the information, the cost is low for a few days of access.

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  • 5 years later...

Hi, Carl:

          My 1993 Lexus LS400 EGR valve malfunction, I tried to tested it by the same procedure as IAC valve, but only click sound, not valve movement. I google search and found out you had the same problem before. Have you got the answer? Do you know can I use

25630-50020 (EGR valve for 95-00 LS400) instead of 25620-50020?


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The last time WeSki was on the site was 2017.  It's doubtful that you'll get a response.

I can't help you with testing, I might be able to help you with the part number.

1993 shows two different EGR valves for 1993 -

25620-50010 - 1990, 1991, 1992, 1993

25620-50020 - 1993, 1994

Both EGR valves are no longer available from the dealer.  However, because it appears that 1993 was a change-over year for the EGR (1993 used wither one or the other), the best way to go is to either:

1) Go to the dealer with your VIN and they can tell you which valve is correct.

2) Go to a Lexus dealership's web site (ex: https://parts.lexusofroseville.com/) and search yourself.

Once you have the Toyota/Lexus part number, you can search the aftermarket for a valve:




Last resort: https://www.ebay.com/

Desperate last resort: https://www.amazon.com/

Good luck.

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